This project focuses on the late complications of therapy for cancer in childhood or adolescence. Mortality and morbidity, especially second cancers, and fertility of long-term survivors of childhood and adolescent cancer are studied for information on the carcinogenicity, gonadal toxicity, and possible mutagenicity of cancer treatment, to uncover hereditary patterns of cancer, and to delineate the factors that predispose to second cancers. Current phases include analysis of data collected from interviews with 593 survivors of leukemia in childhood and 409 of their brothers and sisters as controls (The Leukemia Follow-up Study), and an imaging study of women who had Wilms' tumor to determine the frequency of uterine anomalies. With data from the Five Center Study, a large interview study with survivors of many types of childhood and adolescent cancer, we are studying the late mortality of long-term survivors, and how alterations in the timing of menarche affect timing of menopause. Date from the Surveillance, Epidemiology and End Results program are being analyzed for mortality beyond five years in order to document severe toxicity of therapy and to seek later-onset diseases associated with cancer, in order to shed light on cancer etiology.